\(71\cdot64+32\cdot\left(-7\right)-13\cdot32\)

\(=32\cdot2\cdot71+32\cdot\left(-7\right)+32\cdot\left(-13\right)\)

\(=32\left(142-7-13\right)\)

\(=32\cdot122=3904\)

Lời giải:
a.

$21\times 23-3\times 7\times (-17)$

$=21\times 23-21\times (-17)$

$=21\times 23+21\times 17=21\times (23+17)=21\times 40$

$=840$

b.

$42\times 3-7\times [(-34)+18]$

$=7\times 18-7\times (-16)$

$=7\times 18+7\times 16=7\times (18+16)=7\times 34=238$

c.

$=142\times 32+32\times (-7)-13\times 32$

$=32\times (142-7-32)=32\times 103=3296$

d.

$=13\times [(23-17)-(23+17)]$

$=13\times (23-17-23-17)=13\times (-34)=-442$

58x42+32x8+5x16

=2436+256+80

=2772

tick đúng cho mình nha các bạn!^_^

( - 28 ) x ( -32 ) + 32 x ( 100 - 28 )

= 28 x 32 + 32 x 100 - 32 x 28

= 32 x ( 28 + 100 - 28 )

= 32 x 100

= 3200

(-28).(-32+32).(100-28)

=(-28).(-32)+32.100-28

=[(-28)-28].[(-32)+32].100

=(-56).0.100

=0

ccccccccai

\(32x^2-8x+11\)

\(=32\left(x^2-\frac{1}{4}x+\frac{11}{34}\right)\)

\(=32\left(x^2-2\cdot x\cdot\frac{1}{8}+\frac{1}{64}+\frac{335}{1088}\right)\)

\(=32\left[\left(x-\frac{1}{8}\right)^2+\frac{335}{1088}\right]\)

\(=32\left(x-\frac{1}{8}\right)^2+\frac{335}{34}\ge\frac{335}{34}\forall x\)

Dấu "=" xảy ra \(\Leftrightarrow x=\frac{1}{8}\)

@ trần Thanh Phương@ em nhầm chỗ này rồi em:

\(A=32\left(x^2-\frac{1}{4}x+\frac{11}{32}\right)=32\left(x^2-2.x.\frac{1}{8}+\frac{1}{64}\right)+\frac{21}{2}=32\left(x-\frac{1}{8}\right)^2+\frac{21}{2}\)\(\ge\frac{21}{2}\)

"=" xảy ra khi x=1/8

Vậy min A=21/2 khi x=1/8

32x+9+7=11

<=> 32x=11-9-7=-5

<=> x=-5/32

32x + 9 + 7 = 11

32x = 11 - 9 - 7

32x = -5

=> x = -5/32

\(32x+9+7=11\)

\(\Leftrightarrow32x=11-9-7=-5\)

\(\Leftrightarrow x=-\frac{5}{32}\)

\(\dfrac{189}{3^{2x-7}}=7\\ \Rightarrow3^{2x-7}=\dfrac{189}{7}\\ \Rightarrow3^{2x-7}=27\\ \Rightarrow3^{2x-7}=3^3\\ \Rightarrow2x-7=3\\ \Rightarrow2x=3+7=10\\ \Rightarrow x=\dfrac{10}{2}=5\)

Vậy x = 5

3232

-7548

-4851

-65

Tích cho mk nha

a, -32 . (-101) = 32 . 101 = 32 . (100+1) = 32 . 100 + 32 = 3232

b,102 . (-74)= -74 . (100+2)= -7400 - 148 = -7548

c,-49 . 99 = -49 .( 100 - 1 ) = -4900 + 49 = -4851 

d, 45 - 5.( 9+13 ) = 45 - 5.22= 45 - 110 = -65